Pressure and temperature control



April 1941- J. L KIMBALL Re. 21,777

PRESSURE AND TEMPERATURE CONTROL SWITCH Original Filed Oct. 12. 19:52 2 Sheets-Sheet 1 INVENTOR.

A1 il 22, 1941. J, KM A L 7 Re. 21,777

PRESSURE AND TEIIIEMTURE CONTROL SWITCH Original Filed Oct. 12, 1932 2 Sheets-Sheet 2 2 INVENTOE.

Reissued Apr. 22, 1941 UNITED STATES \PAT'ENT. OFFICE 7 PRESS! AND CONmL' 7 James Lewis Kimball, Danvers, Mala, a'ssignor to Rnggles-Kiingemann Mtg. 00., Salem, Mass.

Original No. 1,975,851, dated October 9, 1934,

Serial No. 631,486, October 12, 19:2. Application for reissue January 28, 1936, Serial No.

My invention relates to pressure and temperature control apparatus, in which an electrically. reversible motor is included as the operating means for controlling the position and movement of a valve, or like device, used in the control of pressure or temperature, or a combination of both pressure and temperature.

One 01' theobjects of my invention is to so control the motor as to prevent a condition oi o'ver correction and hunting action due to time lag.

A second object is to provide means whereby 190mm. -(c|. ass-74) line 12- through armature 2 and field coil 3, thence through conductor I and switch contact points 5i and 52 when said contacts are closed back to.line

L through conductor 6 eiiecting rotation of the motor in one direction. when contacts II and 12 are closed. current flows from L through armature 2 and fleld coil 8, thence through conductors 8 and 6 back to L effecting operation of the motor the motor is controlled primarily from pressure,

but to modulate the pressure setting from variations in the temperature of the fluid tobe controlled. This last named object is particular- ,ly advantageous inthe control or pressure in space to be heated is brought up to the required temperature. Such an-arrangement has a decided advantage in installations where the control valve is bleeding steam for heating purposes from a high pressure source.

To carry out the objects of invention, the I various elements are associated as illustrated in the accompanying drawings in which Fig. 1 illustrates a schematic drawing showing a heat control system as one embodiment of my invention and 2a diagrammatic drawing 01' the control circuit for operating the heat controlling means.

The drawings show a vertical elevation oi my invention in which two switch arms I! and I! having contact members 52 and 12 are reciprocated between two stationary contacts II and II by means of a cam ll operated by a timing motor II. The switch arms I! and ii are pivoted on a device which is responsive to a condition such as variation in pressure or temperature and constitutes a floating switch element arranged to intermittently control a motor circuitas hereafter described.

An electrically reversible motor, for controlling the position and movement or a valve, or

like device 20 (Fig. 1) for regulating the-pressure thence through riser-28 to the heating coil IL Referring now to Fig.2. Current flows from main in the opposite direction. It will be understood that the arrangement of motor circuit can be varied as required, for motors and motor circuits of varying characteristics in carrying out the purpose of my invention. 7

A flexible bellows .or diaphragm device, responsive to variations in pressure, is shown at Iii, pressure connection being at H. This device is intended to actuate switch arms I! and I! through the connections shown. A temperature responsive device is shown at It, having temperature bulb l5 and flexible connecting tube l6. This thermostatic control is also intended to control the operation of'switch arms I! and i3, but from variations in temperature, it will be understood that either the pressure or temperature responsive device can control the switch arms independently, or they can control the switch arms jointly as the pressure 0! the fluid, or the temperature of the room may require. An increase in pressure will close contact points II and- 12 to operate motor I in the proper direction to close on the fluid pressure, and likewise an increase in temperature of the room will close these same contact points to operate the motor to retard the flow of fluid pressure. It will be understood that there will be some time lag between the time the motor is operated and the time the change in pressure setting becomes eflective at the pressure responsive devices, and for this reason it is desirable to operate the motor under normal changes in thecondition or the fluid intermittently with a-well defined period of rest between periods oi operation. The object being to allow the result of the adjustment of the motor to become eflective at the pressure device before proceeding to a further operation. Likewise in temperature control systems the time lag is even greater and consequently requires longer .periods of, rest between periods of adjustment in order that the heat supply may become eiiective at the periods, reciprocate the switch arms I2 and It to see it there has been any change in the condition of the pressure or temperature, and ii so, make contact and adjust the motor accordingly. Ordinarily, with pressure and temperature at its normal value, contacts are not made by the reciprocating of these contact arms by the cam it, but should there be any variation from neutral position of these arms, through variations in pressure or temperature, then contact will be made and the In the operation 01' my invention, a stop screw II is provided, which can be so adjusted as to prevent the contact arm 13 from dropping to a position where a continuous operation is possible. Or, in other words, the operation of the motor will be in steps of operation, regardless 01 how low the pressure or temperature may be. On the other hand, should there be a sudden rise in either pressure or temperature, the motor can be operated continuously until normal conditions are restored. It will be understood that 'the switch arms I! and I3 are made of non-conducting electric insulating material, and that the spring holds these strips in contact with the face of the earn it.

with the adjustment of the contact arms '12 and II, from either pressure or temperature, the pivot point is at 2|, but when reciprocated by the cam II, the pivot points are at 22. The floating lever 23 and connecting arm 24 provide the necessary means for operating arm 25 and the contact arms I! and ll.

In the operation of my invention, I will assume cations.- Therefore, my invention is not limited,

except by the scope of the appended claims.

' I claim: 1. In a pressure controlled switch the combination of a circuit making and breaking switch having high and low pressure contacts, and two parallel floating switch contact arms, a connecting .link properly spacing said floating contact arms between the high and low pressure contacts, a pressure responsive device pivoted on said link, and means to alternately reciprocate said arms at predetermined intervals to cause intermittent contact at either the high or low pressure position when the pressure on the pres sure responsive device varies from normal.

2. In a pressure controlled switch the combination of a" circuit makingand breaking switch having high and low pressure contacts, and two parallel floating switch contact arms, a connecting link properly spacing said floating, contact -arms between the high and low pressure contacts, a pressure responsive device pivoted on said link, means to alternately reciprocate said arms including a motor driven cam, and means due to a variation of pressure i'romnormal acting on thepressure responsive device for intermittently contacting at either the high or low contact position.

3. Ina pressure controlled switch comprising two parallel movable switch arms having contact points at one end, stationary contacts above and below the movable contacts, a connecting link that the application is to steam pressure control for heating a room, and that under the mofst severe temperature conditions I will say a .5 b. pressure is required .to bring up the temperature 01' the room in the shortest possible time. Now, i

as the room approaches the required tempera ture, the thermostatic element which is subjec l to the temperature of the room, becomes-chee tive, and through the-expansion oi the; fluidwithin the bulb l5 causes the bellows ll toexv pand and thereby operate the motor I to cut oil? the steam supply and consequently reduce the pressure setting of the pressure device ll. Likewise, as the room becomes cold, the thermostatic element contracts and thereby.increases the pressure setting of the pressure device.

To this novel feature is added the timing motor to insure step operation oi the motor I, and thereby prevent a condition oi .over correction and consequent hunting action dueto time lag in the pressure system.

In this application'it will be seen that my invention will not only control the pressure, but "also the temperature within the required limits,

but will result in increased steam economy by preventing over heating.

While I have described the application of my invention. to steam heating control, the same will be found to be of advantage in other-appliproperly spacing said movable switch arms intermediate of the stationary contacts, a pressure responsive device pivoted on said link, a motor driven cam located at the opposite end and between said movable switch arms, means to hold said switch arms in contact with the face of said cam, and arranged to reciprocate said arms by the rotating of said cam without making contact at either 01' said stationary points when the pressure acting on the pressure responsive device is at normal, and for making intermittent contact with either one orthe other stationary contacts when the pressure is respectively above or below normal.

4. In a'switch for the regulation of a condition, comprising a floating switch member op-. erated betweentwo stationary contacts and arranged to be reciprocated by a motor operated cam without making contact at either of said stationary contacts when said switch member is in a central position between said contacts, and

' a device sensitive to variations in said condition pivoted on said switch member and arranged to move said switch member out 01' its central position on a variation from normal in said condition, permitting intermittent contact at either one or the other of said stationary contacts, and means controlled bysaid switch for maintaining said condition at a substantially uniform value.

5. In a control switch for the regulation of a condition, comprising two stationary contact points, a floating switch member arranged to engage said contact points, a device responsive to variations in said condition pivoted on said floating switch m'einb'enmeans to oscillate said float- I ing switch member on said pivot without engaging said stationary contacts when the device responsive to said condition is in its mid-position and for intermittently contacting at either one or the other 01' said stationary contact points,

when variations, in said con'dition moves said sensitivedevice out oi its mid position, and means tions, a floating switch member supporting said moveable contacts, a device responsive to varia-1 tions in said condition pivoted on said floating switch member, means to periodically oscillate said floating switch member without engaging the stationary contacts when said condition is at normal, and for intermittently. contacting at either one or the other stationary. contacts *on variations irom the mean average value of said condition, and means controlled by said switch for maintaining said condition at a substantially uniform value.

7. In a switch for the regulation of a condition comprising a floating switch member having circuit making and breaking contacts at one position, stationary contacts arranged to be engaged by the moveable contacts when the switch member is moved out or a neutral position; a device responsive to variations in said condition pivoted on said floating switch member at a second position, a motor and means operated thereby for reciprocating said floating switch member on said pivot without makingcontact at either stationary contact position when the floating switch member is in its neutral position, and for intermittently contacting at the stationary contacts at pro-determined intervals when said responsive device moves. said switch member out of its neutral position, and means operated by said switch for maintaining said condition at a substantially uniform value.

8. In a pressure system, a motor for controlling the pressure in the system, a switch for controlling the motor, having a neutral position in which it is normally ineii'ective, and two normally eflective positions for controlling the operation of the motor in one or another direction, a device responsive to variations in pressure in the system arranged to operate said switch to either of its effective positions, a second motor co-operating with said pressure device and arranged to periodically reciprocate said switch without operating the flrst named motor when said pressure device is in a neutral position, and for intermittently operating the first named motor in either one or another direction when said pressure responsive device is moved out oi its neutral position.

9. In a pressuresystem, a motor for controlling the proiure in the system, a switch for controlling the motor having a neutral position in which it is normally ineilective, and two normally eflective positions for controlling the operation of the motor in one or another direction, a device responsive to the pressure in the system pivoted. I on said switch and arranged to effect its operation to either or its effective positions, means to periodically oscillate said switch on said pivot with out efl'ecting the operation of said motor when said switch is in its normally ineflective position, and for intermittently operating said motor in either one or another direction when said pressure responsive device is moved out of its nor-' mally ineflective position.

10. In a pressure controlled switch, comprising a hosting switch contact member, a pressure.

responsive device pivoted on said switch, a timing motor co-operating with said pressure device and arranged to reciprocate said switch on said pivot trical temperature controlling apparatus,

. a timing motor and means operated thereby,

at ire-determined intervals to cause intermittent contact under pre-determined conditions of pressure acting on the pressure responsive device.

11. In a pressure controlled switch, the combination of a circuit making and breaking switch having high and low pressure contacts, a pressure responsive device pivoted. on said switch, a timing motor co-operating with said pressure device and arranged to reciprocate said switch on said pivot at pre-determined intervals to cause intermittent contact at either the high or low pressure position when the pressure on the pressure responsive device varies i'rom'normai.

12. A temperature control system of the class described comprising, in combination, an eleca thermosensitive element subjected to the temperature to be controlled, a switchcontrolled thereby, a circuit including said switch and in control 0! said temperature controlling apparatus, said switch having a neutral position in which the operation of the electrical temperature controlling apparatus is not effective and eiIective positions respectively above and below said neutral position adapted to control the rate of heat supply within the limits of operation of the electrical temperature controlling apparatus and including a cam adapted to return said switch from either oi! its effective positions to its neutral position at predetermined intervals between the limits of operation of the'electrical temperature controlling apparatus.

13. A temperatur control system of the class described comprising, in combination, an electrical temperature controlling apparatus, a

thermosensitive element subjected to the tem-" perature to be controlled, 9. switch controlled thereby, a circuit including said switch and in control of said-temperature controlling apparatus, said switch having a neutral position in which the operation 01 the electrical temperature controlling apparatus is not effective. and closed circuit positions respectively above and below said neutral position adapted to control the starting, stopping and reversing'of the electrical temperature controlling apparatus to thereby control the' rate 01' heat supply and a timing motor and means operated thereby for returning Bald switch from either or its closed circuit positions to its neutral position at predetermined intervals between the limits of operation oithe electrical temperature controlling apparatus to thereby effect a step by step control within said limits. a a

14. A temperatur control'system of the class described comprising, in combination, electrical operated apparatus for controlling a supply of heating media to the space to be heated, an electrlc circuit including a switch for controlling the operation of the electrical operated apparatus, means to control said switch including a device responsive'to the temperature or the space to be heated and a device responsive to the condition in accordance with variations in the temperature oi the space to be heated.

15. In an apparatus tor the regulation of a condition comprising, in combination, electrical operated means for controlling said condition,

a device responsive to variations in said condi-- eil'ective positions respectively above and below said neutral position adapted to control the electrical operated means in either one or the opposite direction, and a timing motor and a cam operated by the timing motor adapted to return said switch from either or its efl'ective positions to its neutral position at predetermined intervals between the limits of operation or the electrical operated means.

16. In a modulating system of temperature control comprising, in combination, an electrical temperature controlling apparatus, a thermostat control said valve in steps of operation ineither 01 two directions as a function or-the degree or operation or the thermostat and the pressur responsive device.

18. A heat control system comprising, in comv bination, electrically operated apparatus for con trolling steam supply to a space to be heated, an

electric' circuit including a switch for controlling subjected to the temperature to be controlled, a

switch controlled thereby, a circuit including said switch and in control of the temperature controlling apparatus said switch having a neutral position in which the operation or the electrical temperaturecontrolling apparatus is not eflective and contacting positions respectively above and below said neutral position adapted to control the rate 01' heat supply within the limits of operation or the electrical temperature con-' trolling apparatus and timing motor and means operated thereby including a multiple step cam adapted to return said switch to its neutral position after each step or operation or the electrical temperature controlling apparatus,

17. A heat control system oi. the class described comprising, in combination, electrically operated valve for controlling steam supply to a space to be heated, an electric circuit including a switch for controlling the operational the electrically operated valve, means to control said switch including a device responsive to the pressure of steam tor heating said space. a thermostat mp'onsive'to the temperature oi the space to be heated and a timing means, each cooperating with the other to control said switch, said switch having a neutral position in which the operation of the electrically operated valve is not elective and eflective positions respectively above and below said neutral position adapted to the operation of the electrically operated apparatus, means to control said switch including a device responsive to the pressure of steam for heating said space and a thermostat responsive to the temperature of the space to be heated,

each cooperating with the other to control said switch to first limit the steam pressure for heating said space and then further reduce said pressure in accordance with the rise in temperature within the said space, said switch having a neutral position in which the operation 01 the electrical temperature controlling apparatus is. not eflective and eifective positions respectively above and below said neutral position adapted to control the rate of steam supply as a function of the degree of operation or the pressure re- I sponsive device and said thermostat.

19. In a heat control apparatus comprising, in combination, a valve l'or controlling steam supply to a space to'be heated. a control device adapted to control a source of power for operating said valve in either of two directions, said device having a neutral position in which it is not eii'ective in. operating said valve and effective positions respectively above and below said neutral position adapted to control said valve andits direction of operation, means to control said device including an element responsive to the pressure of steam for heating said space and a thermosensitive element responsive to the temperature of the space to be heated, means for interconnecting said elements including a floating lever and means connecting the last named meanscwith the controlling device whereby said device and said valve are controlled as a function oi the degree or operation of the thermoaensitive element and the pressure responsive element.

alums nmmsu. 

